Abstract: Methods and systems include using downhole data to determine a static bulk modulus of dry rock or rock frame in a porous formation and determine a static bulk modulus of grain minerals in the porous formation. Biot's coefficient for the porous formation can be determined based on the static bulk modulus of dry rock or rock frame and the static bulk modulus of grain minerals. Effective stress of the porous formation can be determined based on Biot's coefficient. Effective stress of the porous formation is used in geomechanical applications, including hydraulic fracturing, wellbore stability analysis, and reservoir integrity assessments.

Abstract: Examples described herein provide a computer-implemented method for deriving textural properties of a reservoir formation. The method includes acquiring multi-frequency dielectric data (?meas). The method further includes applying a dielectric mixing model between different fluid phases to generate an effective fluid permittivity (?fluid) by mixing the permittivity of water and hydrocarbon fluids. The method further includes applying the dielectric mixing model between the effective fluid permittivity (?fluid) and a matrix permittivity (?m). The method further includes minimizing a difference between a measured dielectric response and the dielectric mixing model by optimizing model parameters. The method further includes computing a cementation exponent (m) and a saturation exponent (n) from the multi-frequency dielectric data (?meas). The method further includes estimating a formation property based at least in part on the cementation exponent (m) and the saturation exponent (n).

Abstract: A method of estimating a material mechanical property of a porous material, for an application or objective with a specific application frequency and application strain amplitude, includes estimating an application frequency and an application strain amplitude for use in a targeted application or objective, and constructing a frequency transfer function relating the material mechanical property to measurement frequencies, the measurement frequency range including a measurement frequency different from the application frequency.

Abstract: Examples described herein provide a computer-implemented method for deriving textual properties of a reservoir formation. The method includes acquiring multi-frequency dielectric data (?meas). The method further includes applying a dielectric mixing model between different fluid phases to generate an effective fluid permittivity (?fluid) by mixing the permittivity of water and hydrocarbon fluids. The method further includes applying the dielectric mixing model between the effective fluid permittivity (?fluid) and a matrix permittivity (?m). The method further includes minimizing a difference between a measured dielectric response and the dielectric mixing model by optimizing model parameters. The method further includes computing a cementation exponent (m) and a saturation exponent (n) from the multi-frequency dielectric data (?meas). The method further includes estimating a formation property based at least in part on the cementation exponent (m) and the saturation exponent (n).

Abstract: A method of estimating a material mechanical property of a porous material, for an application or objective with a specific application frequency and application strain amplitude, includes estimating an application frequency and an application strain amplitude for use in a targeted application or objective, and constructing a frequency transfer function relating the material mechanical property to measurement frequencies, the measurement frequency range including a measurement frequency different from the application frequency.

Abstract: Methods and systems include using downhole data to determine a static bulk modulus of dry rock or rock frame in a porous formation and determine a static bulk modulus of grain minerals in the porous formation. Biot's coefficient for the porous formation can be determined based on the static bulk modulus of dry rock or rock frame and the static bulk modulus of grain minerals. Effective stress of the porous formation can be determined based on Biot's coefficient. Effective stress of the porous formation is used in geomechanical applications, including hydraulic fracturing, wellbore stability analysis, and reservoir integrity assessments.

Abstract: Methods and apparatus for evaluation of an earth formation including evaluating a core sample obtained from the formation. Methods include using a change in measurements of at least one stress parameter of the core sample, such as radial strain, axial stress, and acoustic emission counts, over time responsive to an applied stress to estimate imminent rock failure in the core sample. This may include estimating the imminent rock failure using differences between portions of a curve generated based on the measurements. A method employing calculating a rate of change between a plurality of measurements of at least one stress parameter of the core sample over time responsive to an applied stress; and determining a point of imminent failure using the rate of change in the plurality of measurements of the at least one stress parameter is also included.

Abstract: A method for estimating, downhole, elastic properties of a subsurface material having a bedding plane includes extracting a core sample from the subsurface material into a downhole tool, the downhole tool comprising a measurement device having a first source and a first receiver opposing the first source, the first receiver configured to receive a signal from the first source, performing at least five acoustic wave velocity measurements on the core sample in situ within the downhole tool, the measurements including compressional acoustic wave velocities and shear wave acoustic velocities with certain directions of shear acoustic wave polarization using the measurement device, estimating, with a controller, elastic properties of the core sample using the at least five acoustic wave velocity measurements, and providing an output signal comprising the elastic properties to an output signal receiving device.

Abstract: Methods and apparatus for evaluation of an earth formation including evaluating a core sample obtained from the formation. Methods include using a change in measurements of at least one stress parameter of the core sample, such as radial strain, axial stress, and acoustic emission counts, over time responsive to an applied stress to estimate imminent rock failure in the core sample. This may include estimating the imminent rock failure using differences between portions of a curve generated based on the measurements.